1. Field of the Invention
This invention generally relates to steering wheel controls for a vehicle. More specifically, the invention relates to aftermarket steering wheel controls that can provide control signals to a steering wheel control interface.
2. Description of the Related Art
Vehicle owners often seek to replace factory-installed audio and video components with aftermarket components. These aftermarket components often must be hard-wired to a vehicle's factory wiring. This may require that a user connect various power, audio, and video wires, and further that the aftermarket component communicate and operate, in part, through such wiring. Many modern vehicles include controls on their steering wheels for operating factory-installed components. These steering wheel controls (SWC) may, for example, increase the volume of a radio, increase the track of a CD being played, or change from one audio source to another. However, the particular configuration of a vehicle's steering wheel controls differs significantly among vehicle makes, models, and model years. Accordingly, it is very difficult for manufacturers of aftermarket components to provide compatibility between their components and the wide array of steering wheel control configurations.
U.S. Pat. Nos. 7,020,289 and 6,956,952 describe hard-wired interfaces for handling SWC signals. A commercial product similar to such interfaces is a SWI-JACK interface manufactured by the Pacific Accessory Corporation (PAC). The SWI-Jack interface has a wire harness on an input side and an output plug on an output side. To install the input side, an installer first selects a particular wire from among many included on the wire harness. The selection is made based upon a lengthy chart, which indicates suitable wires for particular vehicle makes and models. Once selected, the installer electrically connects the selected wire to a steering wheel audio control wire, which provides an output signal from the steering wheel audio controls. The SWI-JACK interface is geared to audio control wires provided within the steering column or underneath the vehicle's dashboard. To install the output side, the installer couples the output plug to a wired remote-control input on an aftermarket head-unit. Once the input and output sides have been installed, the installer completes installation by adjusting an input switch on the SWI-JACK. The adjustment is made according to the manufacturer of the aftermarket head unit.
There are several drawbacks to an interface such as the SWI-JACK. First, the interface is not designed to function upon installation. Rather, the installer must perform a lengthy programming process, with pressing and releasing the respective buttons on the steering wheel controls according to an installation sequence. The process is not only lengthy, but unforgiving. If the installer does not correctly perform the sequence, he must start the sequence over. Second, there can be several wires provided within a vehicle's steering column or dashboard. As a result, the installer may choose the wrong wire when attempting to electrically connect the interface to the steering wheel audio control wire. This could permanently damage components within the vehicle and compromise vehicle safety. A related drawback results from requiring the installer to choose a particular wire from the many wires of the wiring harness: if the installer selects the wrong wire from the harness, damage or malfunction to either the SWI-JACK or the vehicle can result. Furthermore, an inherent drawback of passive component interfaces, such as the SWI-JACK, is that they are compatible only with a limited number of manufacturers of aftermarket radios.
Another type of interface incorporates wireless transmission to relay SWC signals to the aftermarket component. Products manufactured with this design include the SWI-X interface by PAC and the REMOTE series interface by SoundGate. Generally speaking, these interfaces have a wire harness and an infrared (IR) receiver on an input side, and an IR transmitter on an output side. Installation of the input side proceeds in a manner similar to that described above in connection with the SWI-JACK. Installation of the output side involves mounting and aiming the IR transmitter such that it can communicate with an IR receiver integrated with the aftermarket component.
This design has several limitations, one of which is the lengthy programming process. The input and output sides having been installed, the installer must perform a wireless remote control “learning” process. For each steering wheel audio control button, the installer must use the remote control provided with the aftermarket component to emit an IR signal to the interface's IR receiver. The interface then “learns” the IR signal and stores its signal format for future reproduction, similar to a process used in learning television remote controls. The interface cannot reproduce an IR signal according to the steering wheel audio control inputs until this learning process has been performed.
The wireless interface design also fails to overcome the drawbacks of the SWI-JACK interface. The installer must connect the appropriate steering wheel audio control wire, risking permanent damage and malfunction to the vehicle and the interface. And if the installer incorrectly performs any part of the programming process, he must start over, leading to frustration.
Some methods of communication between a vehicle's electrical components are known. U.S. Pat. Nos. 7,275,027, 6,114,970, 6,823,457, 6,141,710, and 6,396,164 describe interconnections between a factory-configured vehicle bus (OEM bus) and a device bus for aftermarket products and accessories. These interconnections generally use a gateway controller. However, in these devices, the vehicle and device bus structures are pre-determined. In this configuration, the gateway controller merely translates between a single set of OEM bus commands and a single set of device bus commands. Thus, these gateway controllers are tied to a specific vehicle bus and/or device bus architecture. Accordingly, they are inapplicable to universal aftermarket products.
As the above discussion makes clear, there is a need to provide a simple, universal solution for providing SWC inputs of all makes and models to aftermarket radios from a wide variety of manufacturers. In particular, an installer can benefit from a device which automatically detects at its input an SWC signal and which configures itself accordingly. Additionally, installers can further benefit from a device which automatically detects an aftermarket component and which further configures itself accordingly. In this manner, the device allows for a simple “plug-and-play” installation process, reducing the stress and risks of installation for both professional and self-installers.
Installation of a device that automatically configures itself in response to detected SWC signals nevertheless may not provide some vehicle owners with the capability to control their aftermarket components via steering wheel controls. As discussed above, many vehicles include factory-installed SWC, as well as other on-wheel controls, such as those for controlling the vehicle's cruise control, and steering column controls, such as those for controlling the vehicle's turn signals or windshield wipers. (As used herein, the phrase “steering wheel component” and “SWC” refers to both kinds of components.)
Some vehicles, however, may not include factory-installed steering wheel components that are suitable for use in sending SWC signals. This may be the case, for example, where steering wheel stereo controls are optional equipment on a vehicle and the purchaser did not opt to have the controls installed, or where the vehicle is an older model manufactured prior to steering wheel stereo controls being offered as standard or optional equipment. In cases such as these, after a vehicle owner or an installer installs an aftermarket stereo, the owner remains unable control the stereo via steering wheel controls because, simply put, the owner has no suitable SWC components. Or, if the user does have some steering wheel components, these components nonetheless may not be reconfigurable to transmit SWC signals. For example, where a vehicle's only steering wheel components are a turn signal and windshield wiper controls, even were the user able to reconfigure these components to control the aftermarket stereo, doing so would cause the vehicle to lose the functions of the turn signals and windshield wipers.
Some known aftermarket components add certain functionality to a vehicle's steering wheel. For example, the Scosche IPNRFCR remote control, which attaches to a steering wheel, can be used to control an Apple iPod. Similarly, the Pioneer CD-SR100 and Blaupunkt RC-10 remote controls may be used to directly control aftermarket stereos made by those manufacturers. However, these components are configured to communicate with a specific aftermarket stereo; none appear to be able to communicate with a device that provides SWC inputs to various aftermarket radios.
Accordingly, there is an additional need for an aftermarket component that provides the owner of a vehicle with steering wheel controls having suitable SWC inputs for an SWC interface, regardless of which, if any, steering wheel components are factory-installed in the vehicle.